SmartCalcs API: Which endpoint should I use for calculations?
Should I use the rates or taxes endpoint for live sales tax calculations?
The endpoint that we recommend using for sales tax calculations is the /v2/taxes endpoint. This endpoint takes several different factors into account before arriving at the proper calculation. For example, the ship from or ship to addresses might affect the sourcing of the sale which would change the calculation.
How can I make sure that the API considers my nexus states?
Please note that the /v2/rates endpoint will simply return the full combined rate for the queried location. The /v2/rates endpoint does not support nexus determination, sourcing based on a ship from and ship to address, shipping taxability, product exemptions, customer exemptions, or sales tax holidays.
- This is why we recommend using our taxes endpoint to accurately calculate sales tax for an order.
We explain the three ways that TaxJar's SmartCalcs API /v2/taxes endpoint will consider nexus in this "Handling Nexus" section of our API Guide.
This endpoint is meant to be used for customers to build backup rates into their system. If you use /v2/rates you will need to build much more logic on your end to get the right rates applied to your orders where /v2/taxes does it all for you!